WO2001023640A1

WO2001023640A1 - Electric discharge surface treating electrode and production method thereof and electric discharge surface treating method

Info

Publication number: WO2001023640A1
Application number: PCT/JP1999/005363
Authority: WO
Inventors: Akihiro Goto; Toshio Moro
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 1999-09-30
Filing date: 1999-09-30
Publication date: 2001-04-05
Also published as: CH693955A5; US6808604B1; CN1371430A; DE19983980T1; CN1322165C; DE19983980B3

Abstract

An electric discharge surface treating electrode (10) is formed by mixing WC powder (11) with W powder (12) and charging the mixture in a press die for compression molding, and electric discharge is generated between the electrode (10) and a work (16) by an electric discharge surface treating power supply device (17) to deposit components of the electrode (10) fused by discharge heat on the work (16). W, a component of the electrode, reacts with C, a constituent of a working fluid (4), to form a WC-containing hard coat (20) on the work (16) along with WC, a component of the electrode (10). The hard coat formed on the work (16) by electric discharge surface treating can be enhanced in hardness and strength.

Description

Description Electrode for discharge surface treatment, method for producing the same, and discharge surface treatment method

According to the present invention, a discharge is generated between an electrode and a workpiece, and the energy is used to form a hard coating made of an electrode material or a hard coating made of a substance in which the electrode material has reacted with the discharge energy on the surface of the workpiece. The present invention relates to an electrode for discharge surface treatment used for discharge surface treatment, a method for producing the same, and an improvement in a method for discharge surface treatment. Background art

Conventionally, techniques for forming a hard coating on the surface of a workpiece to impart corrosion resistance and wear resistance include, for example, a discharge surface disclosed in Japanese Patent Application Laid-Open No. 5-148615. There is a processing method. In this technology, primary processing (deposition processing) is performed using a green compact electrode, which is a discharge surface treatment electrode formed by mixing WC (tandustane carbide) powder and Co (cobalt) powder and compression molding. This is a method for treating the discharge surface of a metal material, which consists of two steps: performing a secondary process (remelting process) by replacing the electrode with a relatively low electrode consumption such as a copper electrode. This method can form a hard coating with strong adhesion to steel, but cannot form a hard coating with strong adhesion to sintered materials such as cemented carbide. Have difficulty.

However, according to our research, when a material that forms a hard carbide such as Ti (titanium) is used as an electrode for discharge surface treatment and a discharge is generated between the workpiece and a metal material, the process of remelting occurs. It has been found that a strong hard coating can be formed on the metal surface, which is the workpiece, without the need. This is due to the discharge This is because the exhausted electrode material reacts with C (carbon) ′, which is a constituent component of the working fluid, to generate T i C (titanium carbide). In addition, when a discharge is generated between a metal material as a workpiece and a compact powder electrode as a discharge surface treatment electrode made of a metal hydride such as TiH 2 (titanium hydride), T It has been found that a hard coating can be formed more quickly and with higher adhesion than when a material such as i is used. Moreover, the green compact electrode is an electrode for electrical-discharge surface treatment with a mixture of other metals or ceramics hydride such as T i H _2, when a discharge is generated between the metal material as a workpiece, the hardness It is said that a hard coating having various properties such as abrasion resistance can be quickly formed.

Such a method is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-192937. Japanese Patent Application Laid-Open No. HEI9-19237 describes a configuration example of a discharge surface treatment electrode and apparatus used for such a discharge surface treatment. This will be described with reference to FIG. In the figure, 1 is a green compact electrode which is an electrode for electric discharge surface treatment formed by compression molding of TiH2 powder, 2 is a workpiece, 3 is a processing tank, 4 is a working fluid, 5 is a green compact electrode A switching element for switching the voltage and current applied to 1 and the workpiece 2; 6, a control circuit for controlling on / off of the switching element 5; 7, a power supply; 8, a resistor; 9, a formed hard coating It is. With such a configuration, a discharge is generated between the green compact electrode 1 and the workpiece 2, and the discharge energy forms a hard coating 9 on the surface of the workpiece 2 made of steel, cemented carbide, or the like. Can be formed.

The formation of a hard coating made of carbide on a workpiece by such discharge surface treatment is performed by using carbide, which is a component of the hard coating to be formed, as a component of an electrode for discharge surface treatment and forming a coating of the carbide on the workpiece by thermal energy generated by electric discharge. Or a metal forming a carbide or a compound of the metal that is a component of the hard coating to be formed, or a compound of the metal as a component of the electrode for electric discharge surface treatment, It is performed by reacting with the component c of the working fluid by thermal energy to form a hard coating made of carbide on the workpiece.

If the component of the electrode for surface treatment of discharge is made of only a material having relatively high hardness such as carbide, the powder that is the electrode component for surface treatment of discharge cannot be solidified by compression molding by pressing. A material with low target hardness is mixed as a binder. However, if Co (cobalt), which is used as a binder when making a sintered alloy, is mixed as the material for the electrode, it is a material that does not produce carbide, so a hard coating formed on the workpiece The hardness of the steel is low, and it cannot be used for applications requiring high wear resistance. Also, depending on the material of the hard coating formed on the workpiece, the compatibility with the base material of the workpiece may be poor, and in such a case, the adhesion strength of the hard coating becomes weak. is there. Disclosure of the invention

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-described problems, and is capable of increasing the hardness and strength of a hard film formed on a workpiece by the discharge surface treatment. It is an object of the present invention to obtain an electrode for use, a method for manufacturing the same, and a method for treating a discharge surface.

The discharge surface treatment electrode according to the present invention is characterized in that a discharge is generated between the electrode and the workpiece in a machining fluid containing carbon, and the energy of the discharge causes the hard surface containing the metal carbide as a component on the surface of the workpiece. In the discharge surface treatment electrode used for the discharge surface treatment for forming a film, the discharge surface treatment electrode material includes: the metal carbide; and a metal contained in the metal carbide, a compound of the metal, or a hard carbide. Other metals or compounds of these metals.

Further, the metal carbide may be a metal or metal contained in the workpiece material. The compound is a metal carbide.

Further, the discharge surface treatment electrode material contains WC and W. The method for producing an electrode for electric discharge surface treatment according to the present invention includes the steps of: generating a discharge between an electrode and a workpiece in a machining fluid containing carbon; In the method for producing an electrode for discharge surface treatment used for a discharge surface treatment for forming a hard coating containing as the above, a powder of the metal carbide, and a powder of the metal contained in the metal carbide or a powder of the compound of the metal or hard metal A powder of another metal or a compound of the metal which forms a carbide is mixed and compression-molded to form the electrode for discharge surface treatment.

Further, after the wax is added to the discharge surface treatment electrode material, compression molding is performed. Thus, the discharge surface treatment electrode is formed.

The discharge surface treatment method according to the present invention includes: generating a discharge between a discharge surface treatment electrode and a workpiece in a machining fluid containing carbon; and using the energy to generate a metal carbide on the surface of the workpiece. In a method for forming a hard coating containing a component as a hard coating, the metal carbide, a metal contained in the metal carbide or a compound of the metal, or another metal forming a hard carbide or a compound of the metal is used. The above-mentioned electrode for discharge surface treatment is used.

Further, the metal carbide is a metal carbide of a metal or a metal compound contained in the workpiece material.

Since the present invention is configured as described above, there is an effect that the hardness and strength of the hard coating formed on the workpiece by the discharge surface treatment can be increased. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view showing the concept of an electrode for discharge surface treatment and a method of manufacturing the electrode according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram showing a discharge surface treatment method according to Embodiment 1 of the present invention.

FIG. 3 is an explanatory view showing a state in which a film is formed on a workpiece by the discharge surface treatment method according to Embodiment 1 of the present invention.

FIG. 4 is an explanatory diagram showing another example of the discharge surface treatment method according to Embodiment 1 of the present invention.

FIG. 5 is an explanatory diagram illustrating the concept of a method for manufacturing an electrode for discharge surface treatment according to Embodiment 2 of the present invention.

FIG. 6 is a diagram showing an example of a vapor pressure curve of Pettus mixed with an electrode material for discharge surface treatment during compression molding of an electrode for discharge surface treatment according to Embodiment 2 of the present invention.

FIG. 7 is a configuration diagram showing an example of a conventional electrode and device for discharge surface treatment. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1

FIG. 1 is a cross-sectional view showing the concept of a discharge surface treatment electrode and a method of manufacturing the same according to Embodiment 1 of the present invention. In the figure, 10 is a discharge surface treatment electrode, and 11 is a WC. (Tungsten Carbide) powder, 1 2 is \ ¥ (Yongsten) powder, 1 3 is the upper punch of the mold, 1 4 is the lower punch of the mold, 1 5 is the die of the mold, WC powder 1 1 And W powder 12 are mixed, placed in a press die, and compression-molded to form an electrode 10 for discharge surface treatment. As shown in the background art, when the hardness of a hard film formed on a workpiece is increased, the components of the electrode for discharge surface treatment are limited to a material having a higher hardness. It is desirable to use only relatively hard materials such as carbides. Also, depending on the material of the hard coating formed on the workpiece, the compatibility with the base material of the workpiece may be poor, and problems such as weak adhesion strength of the hard coating may occur. It is necessary to mix a material that is compatible with the base material of the workpiece into the electrode for discharge surface treatment.

The invention according to the first embodiment of the present invention is intended to improve the compatibility between a workpiece base material and a hard coating formed on a workpiece while using only a material having a higher hardness as a coating component. As an electrode material for electric discharge surface treatment, a hard metal carbide powder having higher hardness, and a C (carbon) contained in a base material of a workpiece and contained in a machining fluid, reacting with the hard carbide to form the hard carbide. The powder of the material to be formed is mixed and compression-molded to form an electrode for discharge surface treatment.

For example, the electrode for discharge surface treatment 10 in FIG. 1 shows a case where a cemented carbide which is a sintered material of WC and Co is mainly used as a workpiece. The hardness of cemented carbide is micro-Vickers hardness, which is about HV = 130 to 2000. This is because the hardness of WC is about HV = 240, but the overall hardness is reduced due to the mixing of soft Co. The electrode for discharge surface treatment 10 shown in Fig. 1 is composed of WC and W. By using this electrode for discharge surface treatment, a coating of only WC, which is a harder material, can be formed on the workpiece. Can be. In addition, since WC is the same material as the component of the cemented carbide, it has good compatibility with the cemented carbide as the base material, and can realize strong adhesion. FIG. 2 shows a discharge surface treatment method according to Embodiment 1 of the present invention, and FIG. 3 shows a hard coating on a workpiece by the discharge surface treatment method according to Embodiment 1 of the present invention. FIG. In the figure, 3 is a processing tank, 4 is a working fluid containing C as a component, 10 is a discharge surface treatment electrode composed of WC and W, 16 is a workpiece made of cemented carbide, 17 is a discharge surface treatment power supply, 18 is a discharge arc column, and 19 is discharge heat. The electrode component for electric-discharge surface treatment which was melted and moved to the workpiece side, and 20 is a hard coating made of WC. When a discharge is generated between the discharge surface treatment electrode 10 and the workpiece 16 by the discharge surface treatment power supply device 17 in FIG. 2, the discharge heat is generated as shown in FIG. 3 (a). The surface treatment electrode 10 is melted and released between the electrodes, and the discharge surface treatment electrode component 19 which has been melted by the heat of the discharge and moved toward the workpiece adheres to the workpiece 16. Next, as shown in (b) of FIG. 3, W, which is a component of the discharge surface treatment electrode 10, reacts with C, which is a component of the machining fluid 4, to become WC, and the discharge surface treatment electrode 10 becomes WC. A hard film 20 composed of WC is formed on the workpiece 16 together with WC which is a component of 10.

FIG. 4 shows another example of the discharge surface treatment method according to Embodiment 1 of the present invention, in which the workpiece is a steel material. In the figure, 3 is a machining tank, 4 is a machining fluid containing C as a component, 17 is a power supply device for discharge surface treatment, 18 is an arc column for electric discharge, 21 is WC and Fe (iron The electrode for discharge surface treatment consisting of) is a workpiece which is a steel material. As described above, when a film is formed on the workpiece 22 made of steel, by mixing Fe, which is a base material component of the workpiece 22, as a material of the discharge surface treatment electrode 21, A film having strong adhesion can be formed.

Embodiment 2

FIG. 5 is a view showing the concept of a method of manufacturing an electrode for discharge surface treatment according to Embodiment 2 of the present invention, where 10 is an electrode for discharge surface treatment, 11 is WC powder, and 1 2 Is a powder, 23 is a wax such as paraffin, 24 is a vacuum furnace, 25 is a high-frequency coil, and 26 is a vacuum atmosphere. Wax 23 is mixed with powder obtained by mixing WC powder 11 and W powder 12 and compression-molded. By forming a powder electrode, the moldability can be significantly improved. However, since the wax 23 is an insulating material, if a large amount of the wax 23 remains in the electrode, the electric resistance of the electrode increases, and the discharge property deteriorates. Therefore, it is necessary to remove Pix 23. FIG. 5 (a) shows a state in which the green compact electrode mixed with the wax 23 is heated in the vacuum furnace 21. The heating is performed in the vacuum atmosphere 26. It may be in a gas such as argon gas. The green compact electrode in the vacuum furnace 24 is heated by a high frequency coil 25 installed around the vacuum furnace 24. At this time, if the heating temperature is too low, the wax 23 cannot be removed, and if the heating temperature is too high, the wax 23 is sooted and the purity of the electrode is deteriorated. It is necessary to keep the temperature below the temperature at which 23 decomposes and soots. As an example, the vapor pressure curve of a wax having a boiling point of 250 is shown in FIG. When the pressure in the vacuum furnace 24 is kept below the vapor pressure of the wax 23, the wax 23 is evaporated and removed as shown in FIG. 5 (b), and the discharge surface treatment electrode 1 composed of WC and W is used. You can get 0.

In the above description, the discharge surface treatment electrode 10 composed of WC and W and the discharge surface treatment electrode 21 composed of WC and Fe have been described. Of course, other materials can be mixed. For example, if the workpiece is titanium metal and a hard coating is to be formed on the workpiece, TiC (titanium carbide) and Ti (titanium), TiC and Ti C2 (oxidized Titanium) or a combination of T i C and T i H 2 (titanium hydride) can form a film on the workpiece that is compatible with the base material of the workpiece. Industrial applicability

As described above, an electrode for discharge surface treatment according to the present invention and a method of manufacturing the same In addition, the discharge surface treatment method is suitable for being used in a surface treatment related industry for forming a hard coating on the surface of a workpiece.

Claims

The scope of the claims

1. In a machining fluid containing carbon, a discharge is generated between an electrode and a workpiece, and the energy is used for a discharge surface treatment for forming a hard coating containing a metal carbide as a component on the surface of the workpiece. In the electrode for discharge surface treatment, as the electrode material for discharge surface treatment, the metal carbide, a metal contained in the metal carbide or a compound of the metal, or another metal forming a hard carbide or a compound of the metal A discharge surface treatment electrode, comprising:

2. The electrode for discharge surface treatment according to claim 1, wherein the metal carbide is a metal carbide of a metal or a metal compound contained in the workpiece material.

3. The electrode for discharge surface treatment according to claim 2, wherein the electrode material for discharge surface treatment contains WC and W.

4. In a machining fluid containing carbon, a discharge is generated between the electrode and the workpiece, and the energy is used for a discharge surface treatment for forming a hard coating containing a metal carbide as a component on the surface of the workpiece. In the production method of the electrode for discharge surface treatment,

A powder of the metal carbide, and a powder of a metal contained in the metal carbide or a powder of a compound of the metal or a powder of another metal or a powder of a compound of the metal forming a hard carbide are mixed and compression-molded. A method for producing an electrode for discharging surface treatment, comprising forming the electrode for discharging surface treatment.

5. The method according to claim 4, wherein a wax is added to the electrode material for discharge surface treatment, followed by compression molding, and heating at a temperature higher than a temperature at which the wax melts and lower than a temperature at which the soak is generated by decomposition of the wax. Steam the wax A method for producing an electrode for discharge surface treatment, wherein the electrode for discharge surface treatment is formed by removing.

6. In the machining fluid containing carbon, a discharge is generated between the discharge surface treatment electrode and the workpiece, and the energy is used to form a hard coating containing metal carbide as a component on the surface of the workpiece. In the surface treatment method, it is preferable to use an electrode for discharge surface treatment containing the metal carbide, and a metal contained in the metal carbide, a compound of the metal, or another metal forming a hard carbide or a compound of the metal. Characteristic discharge surface treatment method.

7. The discharge surface treatment method according to claim 6, wherein the metal carbide is a metal carbide of a metal or a metal compound contained in the workpiece material.